Abstract
We read with interest the article by Bliddal et al. in Thyroid (1), reporting two cases of fetal goitrous hypothyroidism causing polyhydramnios because of overtreatment of maternal Graves' disease. The authors rightly point out that cordocentesis should only be considered if the thyroid function of the fetus is not reasonably certain and that intra-amniotic thyroxine injections are an invasive method that constitutes a risk to the fetus. Yet, they performed cordocentesis in both of their patients and gave repeated intra-amniotic thyroxine injections (six in patient 1 and two in patient 2). We respectfully submit that, had they waited a little longer after decreasing the dose of antithyroid medication given to the mothers, they could have avoided both cordocentesis and intra-amniotic injections.
In our opinion, the only absolute indication for cordocentesis is when (i) a goiter is found in a fetus borne by a woman without Graves' disease, (ii) fetal thyroid function cannot be inferred from the ultrasound characteristics of the goiter (2), and (iii) intra-amniotic thyroxine injections are needed to reverse progressive polyhydramnios (3). Overtreatment of pregnant women with Graves' disease should be avoided through medical education and/or concentrating their care in specialized centers. If it occurs, it can be promptly corrected by decreasing the dose of antithyroid medication given to the mother and does not require invasive procedures that carry a significant risk of fetal death (4).